Multipole circuit breaker



Jan. 28, 1941. 'R. H. KKNGDON MULTIPOLE CIRCUIT BREAKER Filed April 5, 1937 3 Sheets-Sheet 1 111.5 LLLatLon IN VEN T0 R m y .n A H 4 E Jan. 28, 1941. R H. KgNGDQN 2,229,853

MULTIPOLE CIRCUIT BREAKER Filed April 5, 1937 3 Sheets-Sheet 2 A TTORNE y Filed April 5, 1937 3 Sheets-Sheet 3 INVENTOR Patented Jan. 28, 1941 UNITED STATES PATENT OFFICE MULTIPOLE CIRCUIT BREAKER tion of Michigan Application April 5, 1937, Serial No. 134,935

7 Claims.

This invention relates to electric circuit breakers automatically operable in response to current overload and ore particularly to automatic electric circuit breakers of the multipole type.

One object of the present invention is to provide an improved form of releasing means for a multipole electric circuit breaker which shall provide for release of all the poles upon the occurrence of an overload through any one of them.

Another object of the invention is the provision of a multipole electric circuit breaker in which the current responsive unlatching arrangement includes an intermediate striker member engageable upon release of any one pole to efiect unlatching of the other circuit breaker poles.

Another object of the invention is to provide a multipole automatic electric circuit breaker having a member individual to each pole releasable to effect separation of the cooperating contacts forthe pole which is normally latched in place by means responsive to the current through the pole and in which an auxiliary striker is provided adapted to be engaged by'any one released element to effect unlatching movement of the other latching elements for the other circuit breaker poles.

Other objects and features of the invention will be-readily apparent to those skilled in the art from the following specification and appended drawings illustrating certain preferred embodiments of the invention in which:

Figure 1 is a front elevatlonal view of a circuit breaker according to the present invention with the cover removed and certain parts broken away to show internal parts.

Figure 2 is a vertical sectional view of the circuit breaker shown in Figure 1.

Figure 3 is a detailed perspective view of the common striker element.

' Figure 4 is a broken sectional view showing a slightly modified form of striker element.

The circuit breaker according to the present invention includes a generally cup-shaped insulating base -l having a generally centrally disposed dividing wall 2 serving to insulate the breaker poles from each other. Within each of the compartments formed by the central wall 2 and each side wall of the circuit breaker base is mounted a circuit breaker pole mechanism, the separate poles having certain duplicate parts which will now be described. Each of the poles includes a stationary contact 3 mounted upon a connecter 4 which is supported on an end ledge 5 at the top of the circuit breaker exterior on spun over portions of a metallic insert 6 which receives a stud I and a connecter terminal generally indicated at 8. The chamber about the stationary contact 3 is lined with insulating sheets 9 of fibre or other material and extending into this chamber is a movable contact H carried upon the end of a rigid contact bar ill. The front edge of the bar I2 is provided with a notch l3 which receives the front edge of a slot within the longer leg of a U-shaped member Hi to form a pivotal mounting for the contact bar. The member I4 is guided for rectilinear movement at right angles to the back of the base by means of formations within the base. A connecter I5 is mounted upon an end ledge [6 at the bottom of the breaker by the spun over portion of a metallic insert I1 and has the stud and terminal arrang'ement shown at the top of the breaker. The interior end of the connecter I5 has a central pressed up portion l8 upon which is rigidly secured a bimetallic member I9. Adjustable means indicated generally at 2| is provided for adjusting the calibration of the breaker. A flexible lead 22 interconnects the free end of the bimetallic member l3 and the bar l2 and the end of the bar [2 remote from the contact H is latched in operating position by means of the free end of the bimetallic member 19. A compression spring 23 biases the bar I2 against the stationary contact 3 and the end of the bimetallic member l3 and for rotation about the pivotal engagement of the notch l3 with the member I l. The front edge of the bar 12 is provided with a second notch 24 engageable with the notched edge of the shorter leg of the member l4 and serving as a stop in the released position of the bar. Upon a shaft 25 is pivotally mounted an operating handle 26 having an interior cam surface which includes a flat stable manual Off portion 21 and a resetting tip 28. To close off the top and bottom of the circuit breaker insulating plates 23 are provided and there is provided a common cover plate 3| sealably attached to the base as by spun over portions of metallic rivets and beneath whichis disposed an insulating sheet 32. A light spring 33 is provided on the interior portion of the handle 26 to provide a definite position thereof. I

The single pole mechanism heretofore described is duplicated for. each pole desired in the breaker which, as here illustrated, are two. To form these single poles into a multipole circuit breaker there is provided the auxiliary striker element 34 which is illustrated in perspective in Figure 3 and which includes a hub 35 disposed slots therein. The tops of the slots within the legs 36 constitute abutments 31 adapted to be engaged by the contact bars I! when they are released. The ends of the legs 36 are provided with strike portions 38 adapted to engage with the free ends of the bimetallic members l9. Stops.

39 are provided on the hub 35 to limit the rotation thereof in a counter-clockwise direction as viewed in Figure 2. The exterior portions of the operating handles 26 are rigidly connected totogether by means of the U-shaped metallic ele--' ment 4| which joins them together for common movement as a unit.

The operation of the circuit breaker will now be described. The parts are shown in Figures 1 and 2 in their closed circuit position. Rotation of the handles 26 in a clockwise direction as viewed in Figure 2 until the flat portions 21 engage the top faces of the members [4 will cause the members l4 to move toward the back of the base and effect rotation of the bars l2 about their engagements with the bimetallic elements l9 to move the contact surfaces II to a disengaged position to effect manual opening of the circuit. To again place the parts in closed circuit position the handles are rotated in a counterclockwise direction whereupon the contact surfaces I I again engage the contact surfaces 3 under the bias of springs 23. Upon the occurrence of an overload through any one of the circuit breaker poles the bimetallic member I9 for that-pole will become heated and will flex downwardly releasing the end of the corresponding contact bar I2 which then rotates in a clockwise direction under the bias of compression spring 23 about its pivotal engagement with the longer leg of the member l4. This effects movement of the bar into the position shown in broken lines in Figure 2 which is the automatic trip position of the circuit breaker pole. Adjacent the extreme of this movement a portion of the bar I2 adjacent to its latching end engages with the abutment 31 on the striker 34 and forces it'to rotate in a clockwise direction. In this rotation the strike portions 38 engage with the unafiected bimetallic members l9 and mechanically force them to unlatching position releasing the contact bars of the. other breaker poles. With this means it is seen that upon current responsive release of any of the breaker poles the other poles will be positively mechanically opened. To reset the circuit breaker after an automatic release the handles 26 are rotated in a clockwise direction until the resetting tips 28 engage the top surfaces of the members l4 to force them toward the bottom of the base. In this movement the contact carrying ends of the bars l2 engage with the bottoms of the arcing chambers and then rotate about their engagement with the members I4 into a position where they are in 1 back of the latching ends of the bimetals l9. Assuming that the affected bimetal has now cooled sufliciently to resume its latching position, release of the handles will cause the parts to assume the manual open position whereupon rota- 1 tion of the handle in a counter-clockwise direction will again permit the parts to assume the closed circuit position:

Figure 4 illustrates a slightly modified type of mnlatching means for a multipole circuit breaker in which the parts are the same as previously described except that the striker 42 has bifurcated legs 43 which are provided with cam surfaces 44 engageable by a pin 45 rigidly supported on the contact bar l2 to effect the common unlatching movement. In the operation of this type of striker, when the contact bar is released the pin 45 riding over the cam surface 44 forces the striker 42 into engagement with all the bimetals and the pin thereafter, riding over the top portion of the cam surface, enters a depression on this surface which permits the striker to go back and releases the mechanical strain upon the bimetallic members and prevents the possibility of their taking a permanent set. With this type of striker the poles are also opened more nearly simultaneously but the striker is not quite as positive in its operation since the end of the bar I! is not moving with any particular momentum when it engages the cam surface 44 whereas in the preferred embodiment the bar will have picked up considerable speed and will strike the abutment 31 a sharp blow to render the opening movement of ,the unaffected breaker poles more positive.

While certain preferred embodiments of the invention have been specifically disclosed it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and the invention said breaker poles engageable by any elementwhich is released by its current responsive latch, said common means being movable by the released element into engagement with the other latching means to effect opening movement thereof to release the other elements and interrupt the circuit through all the breaker poles in response to an overload through any one of them.

2. In a multipole automatic electric circuit breaker a plurality of pairs of separable contacts, elements individual to each pair releasable to effect separation thereof, individual current responsive latching means for each of said elements, each of said latching means being independently operable to unlatching position upon the occurrence of an'overload through the pair of contacts with which the element which it Jul latches is associated, a common striker memher, and interengaging portions on said striker member and said elements operating to cause said striker to move all the current responsive means to unlatching position in response to release of any one element by its associated latching means.

3. A multipole automatic electric circuit breaker comprising a plurality of pairs of separable contacts and elements individual to each pair releasable to effect separation of the corresponding pairs of contacts, individual current responsive latching means for said elements, each independently operable to unlatching position upon the occurrence of an overload through the pair of contacts with which the element which it latches is associated, a common movable member adapted to engage all of said latching means, each of said elements being engageable with said member when released by its associated latching means to eflect movement of the member and through it of the unaflected latching means to unlatching position, whereby to effect release of all of the elements in response to release of any one of them by its current responsive latching means.

4. A multipole automatic electric circuit breaker comprising a plurality of pairs of separable contacts and elements individual to each pair releasable to effect separation of the corresponding pair of contacts, individual current responsive latching means for said elements, each individually operable to unlatching position upon the occurrence of an overload through the pair of contacts with which the element which it latches is associated, a common striker adapted to engage all of said latching means, a plurality of abutments on said striker, and a surface on each element adapted to engage an abutment with a relatively sharp blow near the end of its movement when released by its latching means, whereby to force said striker into en'- gagement with the other latching means to move them to unlatching position and to effect opening of all the breaker poles in response to release of any one element.

5. A multipole automatic electric circuit breaker comprising a plurality of pairs of separable contacts and elements individual to each pair releasable to effect separation of the correspondingpair of contacts, individual current responsive latching means for said elements, each independently operable to unlatching position upon the occurrence of an overload through the pair of contacts with which the element which it latches is associated, a common striker adapted to engage all of said latching means, cam surfaces on said striker. and means on each element engageable with a cam surface when the element is released by its latching means, the element thereafter causing movement of the V striker intoengagement with the unaffected latchingmeanstomovetliemtounlatching position whereby all of said elements will be reing pair of contacts, individual current responsive latching means for said elements, each independently operable to unlatching position upon the occurrence of an overload through the pair of contacts with which the element which it latches is associated, a common striker adapted to engage all of said latching means, cam surfaces on said striker, and means on each ele-' ment engageable with a cam surface when released by its latching means, the released element thereafter causing movement of the striker into engagement with the unaffected latching means to move them into unlatchlng position in response to the release of any one element b its latching means, said cam surfaces being shaped to effect release of the pressure of said striker upon the latching means in the fully released position of said elements.

'7. A multipole automatic electric circuit breaker comprising a plurality of pairs of separable contacts and elements individual to each 'pair releasable to effect separation of the corresponding pair of contacts, current traversed bimetallic members individual to each of the poles and engageable with said elements to restrain opening movement thereof, each of said bimetallic members being independently operable to unlatching position upon the occurrence of an overload through the pair of contacts with which the element which it latches is associated, means common to the breaker poles mechanically engageable with the bimetallic members to move them, to unlatching position, and intereng -B w D rtions on said common means and said elements whereby any element released by its bimetallic member will effect movement of the common means and through it movementof the bimetallic members into unlatching, position, whereby all of the elements will be released upon the release of any one of them by its bimetallic member so that the circuit through all the poles of the circuit breaker will be opened in response to an overload through any one of them.

- RALPH H. KINGDON. 

